linux-kernel - Re: [RFC PATCH v1] can: m_can: m_can_read_fifo: fix memory leak in error branch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20211029113405.hbqcu6chf5e3olrm@pengutronix.de>
Date:   Fri, 29 Oct 2021 13:34:05 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Vincent Mailhol <mailhol.vincent@...adoo.fr>
Cc:     linux-can@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Matt Kline <matt@...bashing.io>,
        Sean Nyekjaer <sean@...nix.com>,
        Chandrasekar Ramakrishnan <rcsekar@...sung.com>
Subject: Re: [RFC PATCH v1] can: m_can: m_can_read_fifo: fix memory leak in
 error branch

On 27.10.2021 03:09:09, Vincent Mailhol wrote:
> In m_can_read_fifo(), if the second call to m_can_fifo_read() fails,
> the function jump to the out_fail label and returns without calling
> m_can_receive_skb(). This means that the skb previously allocated by
> alloc_can_skb() is not freed. In other terms, this is a memory leak.
> 
> This patch adds a new goto statement: out_receive_skb and do some
> small code refactoring to fix the issue.

This means we pass a skb to the user space, which contains wrong data.
Probably 0x0, but if the CAN frame doesn't contain 0x0, it's wrong. That
doesn't look like a good idea. If the CAN frame broke due to a CRC issue
on the wire it is not received. IMHO it's best to discard the skb and
return the error.

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)